Closing devices known hitherto with pipe-shaped closing elements filling the inside diameter of openings of containers or pipes do not permit an equalization of the tolerances of the inside diameter of the openings as they occur in the production of pipes or containers. It is obvious that such closures cannot withstand an unbalanced pressure occuring, be that now an excess pressure inside the pipe or container or an underpressure therein, so that said closures, particularly in case of suddenly occuring pressure differences, are forced out of the openings. Closing devices in the case of which a sealing ring is pressed against the wall of the opening by two discs moveable against each other by means of a screw, are also known.
The disadvantage of these closing devices lies in the great expenditure of force and time which is required for the tightening of this screw, mostly by means of a wing nut or by means of a wrench. In the case of special work, especially for example, in the case of pipe testing, it is necessary, however, to have a pressure-resistant closure by which a fluid pressure agent, for example water, air, gas or the like, may be quickly introduced or drawn off.